1. CONTACTS AND CONTOURS Presented By Faisal Al-garni 5492
Ezzeldeen Al-hilou 5143
Naif Al-harbi
Adnan Zainaldeen 5327
Sobhi al-saygh

2. CONTENTS Introduction Contours
Contours of the facial and lingual surface
Problems of over or under contouring of the facial and lingual surface
Contours on the proximal surface
Proximal contact
Importance of contact
Size of contact
Embrasures
Procedures for developing correct contact and contour

3. INTRODUCTION
A healthy dentition comprises of fully erupted teeth with proper occlusal and proximal contacts that help to stabilize and maintain the integrity of the arch . All the teeth have tendency toward mesial drift ,which is primarily resisted by contact point of adjacent teeth. Decay in the proximal surface occurs mainly due to faulty inter-relationship between contact area ,marginal ridges, embrasures, and gingiva. A clinicians role is to re-establish the original or correct the faulty contact to form physiologically stable contact & inabilty to restore this relationship disrupts harmony and can result in deleterious consequences like food impaction ,caries,drifting ,tilting or rotation of teeth.

4. CONTOURS
All teeth have some specific convexity on the facial ,lingual , proximal and occlusal surface of teeth that afford the protection and stimulation of the supporting tissues during mastication. This convexity are called contours.
TYPES:
Faciolingual contour.
Proximal contour .
Occlusal contour.

5. Contours on the facial and lingual surface
Facial surface - cervical one third of all teeth
Lingual surface - cervical one third of incisor and canines
-Middle one third of the premolar and molar

6. Problems of over or under contouring of the facial and lingual surface
Over contoured restoration They deflect food from the gingiva causing poor gingival stimulation. The gingiva become flabby ,red and chronically inflamed due to increased plaque retention Under contoured restoration This result in irritation and trauma to the attachment apparatus.

7. Contours on the proximal surface
Teeth show convexities on the distal and mesial surface. The area with maximum convexity on the proximal surface is called the proximal height of contour. Proximal height of contour responsible for the creation of the
a)Proximal contact
b)Embrasure space

8. Proximal contact
Proximal convexity of the teeth create area of contact between adjacent teeth with in the same arch. These are called proximal contact area. Initially as teeth erupt the teeth contact each other at a point(point contact). With the passage of time, physiologic tooth movement causes frictional wear enlarging the contact point to contact area.

9. Importance of contact
Preserves the stability and integrity of the arch by maintaining normal mesio distal relation ship of teeth.
Prevent food impaction interdentally
Protect the soft tissue from periodontal disease
conserve the teeth from proximal caries
Premature restorative failure does not occur if stable proximal contact is present.

10. Size of contact Anteriorly- contact point
Posteriorly –contact area about 1.5-2mm
LOCATION OF CONTACT
Anterior teeth – incisal one third
Posteriorly junction of incisal and middle one third

11. Embrasures
Embrasures are v shaped spaces present interproximally around the proximal contact existing between the adjacent teeth.
Types:
1.Buccal embrasure
2.Lingual embrasure
3.Incisal/occlusal embrasure
4.Gingival embrasure

14. Functions of Embrasures
1)Serve as spillways for the escape of food during mastication. 2) Prevent trapping of food in to the contact area. 3)Protect the underlying supporting tissue during mastication.

15. Problems associated with faulty reproduction of contacts in restoration:
Improper contact size
Too broad contact
It will change the tooth anatomy
It will change the interdental ‘col’ by broadening it. The delicate non keratinized epithelium may get damaged increasing the chance of periodontal tissue.
With too broad contact the interdental area is difficult to clean increase the risk of future decay.

16. Too Narrow contact It will change the tooth anatomy
The embrasure size will increase leading to impaction of food vertically and horizontally, thereby damaging periodontal tissue.

17. Improper contact location
If Contact are placed :
Too occlusally -It will cause flattening of marginal -
ridges, resulting in too shallow occlusal embrasure.
Too buccally/lingually - will encroach upon the
respective embrasure.
Too gingivally will reduce the size of gingival embrasure, and encroach upon interdental gingiva.

18. Open contact
Open contacts would create the problem ready inflow of food causing accumulation of debris , plaque and damage to the periodontal disease

19. Procedures for developing correct contact and contour:
To create proper contact and contour with any restorative material, the teeth have to be first separated and then a temporary wall created to support the restorative material in plastic stage.
Tooth separation to create space between adjoining teeth.
Matrix application on the prepared proximal side.

20. RAPID SEPARATION
This is immediate type of separation . This type of tooth movement involves separation of teeth proximally at the point of insertion of separator. The amount of separation produced should not exceed mm. Rapid separation can be done by two method : a) Wedge method b) Traction method

21. Wedge method of separation
In this method space is created by inserting wedge shaped device between the teeth. There are two types of separator 1)Wooden / Plastic wedges 2)Elliot separator

22. Classification of Wedges
1) On the basis of method of fabrication :
a) Custom made wedges .
b) Pre fabricated wedges .
2) On the basis of material used for fabrication:
a) Wooden wedges .
b) Plastic or synthetic resin wedges.

23. Custom made wedges
These are made by trimming wood or plastic material in triangular shape to mach that of embrasure. Trimming can be done by scalpel , gold knife or diamond stone.

24. Wooden wedges
These wedges are made from wood. It may be soft and resilient or hard .they are easy to trim and shape. They absorb water interiorly and swell up ,which causes them to press more press against the matrix there by improving their retention. They are available in two shape. 1)Triangular shape 2)Round shape

25. Triangular Shape Wedges
These are most commonly used.
Indicated in cavities with deep gingival margin
Used to depress the rubber dam
They are preferred in ideal class II cavities preparation as wedging action close to the gingival margin
Round shape wedges

26. Light transmitting wedges
These are transparent plastic wedges ,which are available in with built in light reflecting property.
Indication
Class II composite restoration : These light transmitting wedges help to assist in directing light into inter proximal areas during initial stages of class II composite curing .

27. Piggy- Back Wedging
Useful in cases with gingival recession of inter- proximal tissue . In such cases when the wedge lies in the apical margin of proximal cavity another wedge smaller in size is piggy backed on the first one to fill the space and press the matrix band against the margin.

28. Functions of wedges
They create space between teeth to compensate the thickness of matrix band.
Immobilize the matrix band.
Closely press the matrix band against the tooth in the gingival area of the preparation preventing any restorative material escaping below the band.
Maintaining the health of interdental gingiva by preventing material from impinging.
Protect the gingiva from unexpected truma.

29. Matricing
Is a procedure by which a temporary wall is created opposite to axial wall that surrounds the area of the tooth structure, which was lost during tooth preparation.

30. Matrix
Is a device which used to confine and give shape to the restorative material during its introduction and hardening. the matrix assembly consist of two parts:
1) Matrix band
2) Matrix retainer

31. Matrix band
It is a false wall in the form of thin piece of metal or other material ,replacing the missing wall in cavity preparation. it may be of different material such as stainless steel ,(toffelemire,ivory bands ),copper(copper bands),celluloid(transparent strips).
The height of the band should be such that it extend 2mm above the marginal ridge and 1mm below gingival margin of the preparation.
Matrix retainer : it is an instrument used to hold matrix band in position.

32. Ideal requirements of Matrix
It should be simple in design.
It should be easily applied and readily removed
It should be rigid enough to withstand condensation pressure preventing the restorative material bulging out.
It should be able to adapt with the shape and position of different types of tooth. It should be non reactive to the tissue and restorative material.
It should be inexpensive and readily available.
It should be easy to sterilize.

33. Functions of Matrix It act as a temporary supporting wall
It confines the restorative material and allow it to acquire proper shape and form as it harden.
It retracts the gingiva and rubber dam as the restorative material packed in the cavity.
It helps to establish the proper contact and contours.

34. Matrix band Indication: It is ideally indicated for MOD cavities
Class II cavities
Class I cavities with buccal and lingual extensions

35. Conclusion
It is essential to have adequate knowledge about the anatomical and functional aspects of contacts and contours so as to reproduce them with ideal restorative material which will help o maintain the oral cavity in sound health.

36. Reference
A B DENTATUS (1981) Technical Pamphlet, A B Dentatus, Stockholm, Hagersten, Sweden.
ABERNETHY, MW (1937) Taylor-made matrixes Dental Digest
ANDREWS, R R (1886) Discussion In Brophy, T W ( 1886) The matrix - a new form Dental Cosmos
BAKER, H A (1886) Cited by Andrews, R R in Brophy, TW(1886)The matrix-a newform Dental Cosmos
BAUM, L (1974) Operative Dentistry for the General Practitioner: Some Useful Applications of Pins and Other Material pp Springfield, Ill: Charles Thomas.
BENNETT, S (1885) On Herbst's Method of Gold-Filling by Rotating Burnishers pp 1-23 London: Harrison & Sons.
BERK, H (1945) Matrices for compound amalgam restorations Journal of Dentistry for Children
BIALES, L B (1944) The mesiocclusodistal matrix Journal of the American Dental Association
BJORNCRANTZ, CR (1981) Personal communication. AB Dentatus, Stockholm, Hagersten, Sweden.
BLACK, AD (1936) G V Black's Work on Operative Dentistry 7th edition Vol II pp , Chicago: Medico-Dental.
BLACK, G V (1890) The inter-proximal spaces Dental Review
BLACK, G V (1899) The Technical Procedures infilling Teeth pp5-151 Chicago:HenryO Sheppard.